Processes for preparing metallocene-based catalyst systems for the control of long chain branch content

ABSTRACT

Methods for preparing a metallocene-based catalyst composition that can impact the long chain branching of ethylene homopolymers and copolymers produced using the catalyst composition are described. The catalyst composition can be prepared by contacting a metallocene compound, a hydrocarbon solvent, and a first organoaluminum compound for a first period of time to form a metallocene solution, and then contacting the metallocene solution with an activator-support and a second organoaluminum compound for a second period of time to form the catalyst composition.

FIELD OF THE INVENTION

The present disclosure concerns metallocene catalyst systems, and moreparticularly relates to methods for preparing the metallocene catalystsystems that impact the long chain branch (LCB) content of olefin-basedpolymers produced using the catalyst systems.

BACKGROUND OF THE INVENTION

There are various methods used to prepare metallocene-based catalystsystems containing an activator-support. These catalyst systems can beused to polymerize olefins to produce olefin-based polymers, such asethylene/α-olefin copolymers. For the same metallocene compound andactivator-support components of the catalyst system, it would bebeneficial for these catalyst systems to produce polymers having eitherhigher or lower LCB content, as a result of the method used to preparethe catalyst system. Accordingly, it is to this end that the presentdisclosure is generally directed.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

In one aspect of this invention, processes to produce a catalystcomposition are disclosed, and in this aspect, the processes cancomprise (a) contacting a metallocene compound, a hydrocarbon solvent,and a first organoaluminum compound for a first period of time to form ametallocene solution, and (b) contacting the metallocene solution withan activator-support and a second organoaluminum compound for a secondperiod of time to form the catalyst composition.

In another aspect of this invention, catalyst compositions aredisclosed, and in this aspect, one such catalyst composition cancomprise (i) a metallocene solution comprising a metallocene compound, ahydrocarbon solvent, and a first organoaluminum compound, (ii) anactivator-support, and (iii) a second organoaluminum compound. Anothercatalyst composition disclosed herein can comprise (i) a metallocenesolution comprising rac-ethylene-bis(indenyl) zirconium dichloride, ahydrocarbon solvent, and a first organoaluminum compound, (ii) anactivator-support, and (iii) a second organoaluminum compound. Yetanother catalyst composition disclosed herein can comprise (i) ametallocene solution comprising methyl(buten-3-yl) methylidene(η5-cyclopentadienyl) (η5-2,7-di-tert-butylfluoren-9-ylidene) zirconiumdichloride, a hydrocarbon solvent, and a first organoaluminum compound,(ii) an activator-support, and (iii) a second organoaluminum compound.

In yet another aspect of this invention, polymerization processes aredisclosed, and in this aspect, the processes can comprise (A) contactinga metallocene compound, a hydrocarbon solvent, and a firstorganoaluminum compound for a first period of time to form a metallocenesolution, and contacting the metallocene solution with anactivator-support and a second organoaluminum compound for a secondperiod of time to form a high LCB catalyst composition, (B) contactingthe metallocene compound, the hydrocarbon solvent, theactivator-support, and the second organoaluminum compound to form a lowLCB catalyst composition, (C) contacting the high LCB catalystcomposition and/or the low LCB catalyst composition with ethylene and anoptional olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an ethylene polymer having a longchain branch (LCB) content, and (D) controlling a relative amount of thehigh LCB catalyst composition and the low LCB catalyst composition instep (C) to adjust the LCB content of the ethylene polymer.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations may be provided inaddition to those set forth herein. For example, certain aspects may bedirected to various feature combinations and sub-combinations describedin the detailed description.

Definitions

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997), can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter are described such that, withinparticular aspects, a combination of different features can beenvisioned. For each and every aspect and/or feature disclosed herein,all combinations that do not detrimentally affect the compositions andprocesses described herein are contemplated with or without explicitdescription of the particular combination. Additionally, unlessexplicitly recited otherwise, any aspect and/or feature disclosed hereincan be combined to describe inventive features consistent with thepresent disclosure.

In this disclosure, while compositions and processes are often describedin terms of “comprising” various components or steps, the compositionsand processes also can “consist essentially of” or “consist of” thevarious components or steps, unless stated otherwise.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “apolymerization reactor” or “a metallocene compound” is meant toencompass one, or combinations of more than one, polymerization reactoror metallocene compound, unless otherwise specified.

For any particular compound or group disclosed herein, any name orstructure (general or specific) presented is intended to encompass allconformational isomers, regioisomers, stereoisomers, and mixturesthereof that can arise from a particular set of substituents, unlessotherwise specified. The name or structure (general or specific) alsoencompasses all enantiomers, diastereomers, and other optical isomers(if there are any) whether in enantiomeric or racemic forms, as well asmixtures of stereoisomers, as would be recognized by a skilled artisan,unless otherwise specified. For instance, a general reference to pentaneincludes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; and ageneral reference to a butyl group includes a n-butyl group, a sec-butylgroup, an iso-butyl group, and a t-butyl group.

The term “hydrocarbon” whenever used in this specification and claimsrefers to a compound containing only carbon and hydrogen. The term“hydrocarbyl group” is used herein in accordance with the definitionspecified by IUPAC: a univalent group formed by removing a hydrogen atomfrom a hydrocarbon (that is, a group containing only carbon andhydrogen). Non-limiting examples of hydrocarbyl groups include alkyl,alkenyl, aryl, and aralkyl groups, amongst other groups.

The term “polymer” is used herein generically to include olefinhomopolymers, copolymers, terpolymers, and the like, as well as alloysand blends thereof. The term “polymer” also includes impact, block,graft, random, and alternating copolymers. A copolymer can be derivedfrom an olefin monomer and one olefin comonomer, while a terpolymer canbe derived from an olefin monomer and two olefin comonomers.Accordingly, “polymer” encompasses copolymers and terpolymers.Similarly, the scope of the term “polymerization” includeshomopolymerization, copolymerization, and terpolymerization. Therefore,an ethylene polymer would include ethylene homopolymers, ethylenecopolymers (e.g., ethylene/α-olefin copolymers), ethylene terpolymers,and the like, as well as blends or mixtures thereof. Thus, an ethylenepolymer encompasses polymers often referred to in the art as LLDPE(linear low density polyethylene) and HDPE (high density polyethylene).As an example, an ethylene copolymer can be derived from ethylene and acomonomer, such as 1-butene, 1-hexene, or 1-octene. If the monomer andcomonomer were ethylene and 1-hexene, respectively, the resultingpolymer can be categorized an as ethylene/1-hexene copolymer. The term“polymer” also includes all possible geometrical configurations, ifpresent and unless stated otherwise, and such configurations can includeisotactic, syndiotactic, and random symmetries. The term “polymer” alsois meant to include all molecular weight polymers.

The terms “catalyst composition,” “catalyst mixture,” “catalyst system,”and the like, do not depend upon the actual product or compositionresulting from the contact or reaction of the initial components of thedisclosed or claimed catalyst composition/mixture/system, the nature ofthe active catalytic site, or the fate of the hydrocarbon solvent(s),the organoaluminum compound(s), the metallocene compound(s), or theactivator-support(s), after combining these components. Therefore, theterms “catalyst composition,” “catalyst mixture,” “catalyst system,” andthe like, can encompass the initial starting components of thecomposition, as well as whatever product(s) may result from contactingthese initial starting components, and this is inclusive of bothheterogeneous and homogenous catalyst systems or compositions. The terms“catalyst composition,” “catalyst mixture,” “catalyst system,” and thelike, may be used interchangeably throughout this disclosure.

The term “contacting” is used herein to describe compositions andprocesses in which the components are contacted or combined together inany order, in any manner, and for any length of time, unless otherwisespecified. For example, the components can be combined by blending ormixing, or by using any suitable technique.

A “metallocene solution” describes a mixture of metallocene, hydrocarbonsolvent, and first organoaluminum components that are combined orcontacted for a first period of time to form a metallocene solution,prior to being contacted with other catalyst components, such as anactivator-support and a second organoaluminum compound. According tothis description, it is possible for the components of the metallocenesolution, once contacted, to have reacted to form at least one chemicalcompound, formulation, species, or structure different from the distinctinitial compounds or components used to prepare the metallocenesolution.

Various numerical ranges are disclosed herein. When a range of any typeis disclosed or claimed, the intent is to disclose or claim individuallyeach possible number that such a range could reasonably encompass,including end points of the range as well as any sub-ranges andcombinations of sub-ranges encompassed therein, unless otherwisespecified. As a representative example, the present disclosure recitesthat the weight ratio of the metallocene compound to theactivator-support in a catalyst composition can be in certain ranges. Bya disclosure that the weight ratio can be in a range from 1:1 to1:100,000, the intent is to recite that the weight ratio can be anyratio in the range and, for example, can include any range orcombination of ranges from 1:1 to 1:100,000, such as from 1:10 to1:10,000, from 1:20 to 1:1000, or from 1:50 to 1:500, and so forth.Likewise, all other ranges disclosed herein should be interpreted in amanner similar to this example.

In general, an amount, size, formulation, parameter, range, or otherquantity or characteristic is “about” or “approximate” whether or notexpressly stated to be such. Whether or not modified by the term “about”or “approximately,” the claims include equivalents to the quantities orcharacteristics.

Although any methods, devices, and materials similar or equivalent tothose described herein can be used in the practice or testing of theinvention, the typical methods, devices, and materials are hereindescribed.

All publications and patents mentioned herein are incorporated herein byreference in their entirety for the purpose of describing anddisclosing, for example, the constructs and methodologies that aredescribed in the publications and patents, which might be used inconnection with the presently described invention.

DETAILED DESCRIPTION OF THE INVENTION

Disclosed herein are methods for preparing catalyst compositionscontaining a metallocene compound, an activator-support, anorganoaluminum compound, and a hydrocarbon solvent. Polymerizationprocesses utilizing these catalyst compositions also are disclosed.

An advantageous and unexpected benefit of the methods/processes andcatalyst compositions disclosed herein is the ability to control thelong chain branch (LCB) content of polymers produced using the catalystcompositions, without having to resort to changing the metallocenecompound or the activator-support components of the catalyst system.

The LCB content is an important property of ethylene-based polymers,such as LLDPE and HDPE. Based on the end-use application of the polymerand the fabrication process used to convert the polymer, it can bedesirable to have either high or low LCBs. For instance, it can bebeneficial to minimize the LCB content for thin-gauge film resins inorder to improve the tear resistance and toughness properties of thefilm product. However, in other applications, higher levels of LCBs areneeded for improved melt strength, die swell, and neck-in during polymerprocessing, such as blow molding or extrusion coating.

Processes for Preparing Catalyst Compositions

Various processes for preparing a catalyst composition containing ametallocene compound, an activator-support, an organoaluminum compound,and a hydrocarbon solvent are disclosed and described. One or more thanone metallocene compound, activator-support, organoaluminum compound,and hydrocarbon solvent can be employed in the disclosed processes andcompositions. A process for producing a catalyst composition consistentwith aspects of this invention can comprise (or consist essentially of,or consist of):

-   -   (a) contacting a metallocene compound, a hydrocarbon solvent,        and a first organoaluminum compound for a first period of time        to form a metallocene solution; and    -   (b) contacting the metallocene solution with an        activator-support and a second organoaluminum compound for a        second period of time to form the catalyst composition.

Generally, the features of any of the processes disclosed herein (e.g.,the metallocene compound, the hydrocarbon solvent, theactivator-support, the first and second organoaluminum compounds, thefirst period of time, and the second period of time, among others) areindependently described herein, and these features can be combined inany combination to further describe the disclosed processes. Moreover,other process steps can be conducted before, during, and/or after any ofthe steps listed in the disclosed processes, unless stated otherwise.Additionally, catalyst compositions produced in accordance with thedisclosed processes are within the scope of this disclosure and areencompassed herein.

Step (a) of the process often can be referred to as the metallocenesolution preparation step, and in this step, a metallocene compound, ahydrocarbon solvent, and a first organoaluminum compound can becontacted for a first period of time to form a metallocene solution.Step (a) can be conducted at a variety of temperatures and time periods.For instance, this step can be conducted at a temperature in a rangefrom 0° C. to 100° C.; alternatively, from 0° C. to 75° C.;alternatively, from 10° C. to 75° C.; alternatively, from 20° C. to 60°C.; alternatively, from 20° C. to 50° C.; alternatively, from 15° C. to45° C.; or alternatively, from 20° C. to 40° C. In these and otheraspects, these temperature ranges also are meant to encompasscircumstances where step (a) is conducted at a series of differenttemperatures, instead of at a single fixed temperature, falling withinthe respective ranges.

The duration of step (a) (the first period of time) is not limited toany particular period of time. Hence, the first period of time can be,for example, a time period ranging from as little as 1-10 sec to as longas 48 hr, or more. The appropriate first period of time can depend upon,for example, the temperature, the amounts of the metallocene compoundand the first organoaluminum compound in the metallocene solution, theamount of the hydrocarbon solvent in the metallocene solution, and thedegree of mixing, among other variables. Generally, however, the firstperiod of time can be at least 5 sec, at least 10 sec, at least 30 sec,at least 1 min, at least 5 min, at least 10 min, and so forth. Typicalranges for the first period of time can include, but are not limited to,from 1 sec to 48 hr, from 5 sec to 48 hr, from 30 sec to 24 hr, from 30sec to 6 hr, from 1 min to 12 hr, from 5 min to 24 hr, from 5 min to 1hr, or from 10 min to 8 hr, as well as ranges within these exemplaryranges.

Often, step (a) can be conducted by contacting a solution of themetallocene compound in the hydrocarbon solvent with the firstorganoaluminum compound. If needed, suitable mixing can be applied toensure sufficient contacting of the metallocene compound and the firstorganoaluminum compound. However, step (a) is not limited thereto, andstep (a) can be conducted by contacting the metallocene compound, thehydrocarbon solvent, and the first organoaluminum compound in any orderor sequence.

A metallocene solution is formed in step (a), i.e., the metallocenecompound is substantially dissolved at standard temperature (25° C.) andpressure (1 atm). This means that there is no visual precipitation ofany solid metallocene compound from the solution. In some aspects, whenthe solution is filtered, the absorbance of the solution of themetallocene compound (when tested at a wavelength in the UV-visiblespectrum of peak absorbance for the metallocene compound) often does notchange by more than 5% from the unfiltered solution.

In step (b) of the process, the metallocene solution can be contactedwith an activator-support and a second organoaluminum compound for asecond period of time to form the catalyst composition. Step (b),likewise, can be conducted at a variety of temperatures and timeperiods. For instance, step (b) can be conducted at a temperature in arange from 0° C. to 100° C.; alternatively, from 0° C. to 75° C.;alternatively, from 10° C. to 75° C.; alternatively, from 20° C. to 60°C.; alternatively, from 20° C. to 50° C.; alternatively, from 15° C. to45° C.; or alternatively, from 20° C. to 40° C. In these and otheraspects, these temperature ranges are also meant to encompasscircumstances where step (b) is conducted at a series of differenttemperatures, instead of at a single fixed temperature, falling withinthe respective ranges. As an example, the components in step (b) can becontacted at an elevated temperature, following by cooling to a lowertemperature for longer term storage of the finished catalystcomposition.

The second period of time is not limited to any particular period oftime. Hence, the second period of time can range from as little as 1-10sec to as long as 48 hr, or more. The appropriate second period of timecan depend upon, for example, the temperature, the relative amounts ofthe metallocene compound in the solution, the activator-support, and thesecond organoaluminum compound in step (b), the degree of mixing, andconsiderations for long term storage, among other variables. Generally,however, the second period of time can be at least 1 sec, at least 5sec, at least 30 sec, at least 1 min, at least 5 min, at least 10 min,and so forth. Assuming the catalyst composition is not intended for longterm storage, which could extend for days or weeks, typical ranges forthe second period of time can include, but are not limited to, from 1sec to 48 hr, from 10 sec to 48 hr, from 30 sec to 24 hr, from 30 sec to6 hr, from 1 min to 6 hr, from 5 min to 24 hr, from 5 min to 1 hr, orfrom 10 min to 8 hr.

Step (b) can be conducted by contacting the metallocene solution, theactivator-support, and the second organoaluminum compound in any orderor sequence. In one aspect, the activator-support and the secondorganoaluminum compound are first combined, followed by addition of themetallocene solution. In another aspect, the activator-support and themetallocene solution are first combined, followed by addition of thesecond organoaluminum compound. In yet another aspect, the secondorganoaluminum compound and the metallocene solution are first combined,followed by addition of the activator-support. In still another aspect,the activator-support, the second organoaluminum compound, and themetallocene solution are contacted or combined simultaneously.

In all aspects of the process for producing a catalyst compositiondisclosed herein, the second organoaluminum compound in step (b) can bethe same as or different from the first organoaluminum compound utilizedin step (a). The first organoaluminum compound in step (a) and thesecond organoaluminum compound in step (b), independently, can bepresent either neat or as a solution in any suitable hydrocarbonsolvent, which can be the same as different from the hydrocarbon solventused in step (a). Likewise, the activator-support in step (b) can bepresent as a dry solid or as a mixture or slurry in any suitablehydrocarbon solvent, which can be the same as or different from thehydrocarbon solvent in step (a).

Related to the above-described catalyst preparation processes arecatalyst compositions. In one aspect, a catalyst composition consistentwith this invention can comprise (i) a metallocene solution comprising ametallocene compound, a hydrocarbon solvent, and a first organoaluminumcompound, (ii) an activator-support, and (iii) a second organoaluminumcompound.

In another aspect, a catalyst composition consistent with this inventioncan comprise (i) a metallocene solution comprisingrac-ethylene-bis(indenyl) zirconium dichloride, a hydrocarbon solvent,and a first organoaluminum compound, (ii) an activator-support, and(iii) a second organoaluminum compound. Unexpectedly, this catalystcomposition can produce ethylene polymers with relatively high LCBcontents. For instance, when (a) an olefin (e.g., 1-hexene) or alkane(e.g., heptane) is used as the hydrocarbon solvent andtriisobutylaluminum is used as the first organoaluminum compound, orwhen (b) an aromatic (e.g., toluene) or an alkane (e.g., heptane) isused as the hydrocarbon solvent and trioctylaluminum is used as thefirst organoaluminum compound, a surprisingly high LCB content canresult.

In yet another aspect, a catalyst composition consistent with thisinvention can comprise (i) a metallocene solution comprisingmethyl(buten-3-yl)methylidene(η5-cyclopentadienyl)(η5-2,7-di-tert-butylfluoren-9-ylidene)zirconium dichloride, a hydrocarbon solvent, and a first organoaluminumcompound, (ii) an activator-support, and (iii) a second organoaluminumcompound. Unexpectedly, this catalyst composition can produce ethylenepolymers with relatively high LCB contents. For instance, when anaromatic (e.g., toluene) is used as the hydrocarbon solvent andtriisobutylaluminum is used the first organoaluminum compound, asurprisingly high LCB content can result.

Generally, in the catalyst compositions and methods of their preparationdisclosed herein, the molar ratio of the first organoaluminum compoundto the metallocene compound can be in a range from 1:1 to 1000:1, suchas from 1:1 to 100:1, from 2:1 to 200:1, or from 5:1 to 100:1, althoughnot limited thereto. If more than one first organoaluminum compoundand/or more than one metallocene compound are employed, this ratio isbased on the total moles of each respective type of component. Likewise,the molar ratio of the first organoaluminum compound to the secondorganoaluminum compound is not particularly limited, and often can rangefrom 1000:1 to 1:1000. Typical molar ratios can include from 100:1 to1:100, from 10:1 to 1:10, from 1:1 to 1:10, or from 1:2 to 1:10, and thelike.

In step (b), the weight ratio of the metallocene compound (present inthe metallocene solution) to the activator-support can range from 1:1 to1:100,000 in one aspect, from 1:10 to 1:10,000 in another aspect, from1:20 to 1:1000 in yet another aspect, and from 1:50 to 1:500 in stillanother aspect. Also in step (b), the weight ratio of theactivator-support to the second organoaluminum compound can range from100:1 to 1:100 in one aspect, from 10:1 to 1:10 in another aspect, from5:1 to 1:5 in yet another aspect, and from 2:1 to 1:2 in still anotheraspect. If two or more of these components are present, then theseratios are based on the total weight of each respective type ofcomponent.

In some aspects, the catalyst compositions and methods of theirpreparation are substantially free of aluminoxane compounds, organoboronor organoborate compounds, ionizing ionic compounds, and/or othersimilar materials; alternatively, substantially free of aluminoxanes;alternatively, substantially free or organoboron or organoboratecompounds; or alternatively, substantially free of ionizing ioniccompounds. In these aspects, the catalyst composition has catalystactivity in the absence of these additional materials. For example, acatalyst composition of the present invention can consist essentially of(i) a metallocene solution comprising a metallocene compound, ahydrocarbon solvent, and a first organoaluminum compound, (ii) anactivator-support, and (iii) a second organoaluminum compound, whereinno other materials are present in the catalyst composition which wouldincrease/decrease the activity of the catalyst composition by more than10% from the catalyst activity of the catalyst composition in theabsence of said materials.

Metallocene Compounds

Metallocene-based catalyst compositions consistent with this inventioncan contain a bridged metallocene compound and/or an unbridgedmetallocene compound. Metallocene-based catalyst compositions consistentwith this invention also can contain two or more bridged metallocenecompounds, two or more unbridged metallocene compounds, or at least onebridged metallocene compound and at least one unbridged metallocenecompound. The metallocene compound can comprise, for example, atransition metal (one or more than one) from Groups IIIB-VIIIB of thePeriodic Table of the Elements. In one aspect, the metallocene compoundcan comprise a Group III, IV, V, or VI transition metal, or acombination of two or more transition metals. The metallocene compoundcan comprise chromium, titanium, zirconium, hafnium, vanadium, or acombination thereof, or can comprise titanium, zirconium, hafnium, or acombination thereof, in other aspects. In further aspects, themetallocene compound can comprise titanium, or zirconium, or hafnium,either singly or in combination.

In some aspects of this invention, the metallocene compound can comprisea bridged metallocene compound, e.g., with titanium, zirconium, orhafnium, such as a bridged zirconium or hafnium based metallocenecompound with a fluorenyl group, or a bridged zirconium or hafnium basedmetallocene compound with a cyclopentadienyl group and a fluorenylgroup. Such bridged metallocenes, in some aspects, can contain analkenyl substituent (e.g., a terminal alkenyl group) on the bridginggroup and/or on a cyclopentadienyl-type group (e.g., a cyclopentadienylgroup or a fluorenyl group). In another aspect, the metallocene compoundcan comprise a bridged zirconium or hafnium based metallocene compoundwith a fluorenyl group, and an aryl group on the bridging group;alternatively, a bridged zirconium or hafnium based metallocene compoundwith a cyclopentadienyl group and fluorenyl group, and an aryl group onthe bridging group; alternatively, a bridged zirconium based metallocenecompound with a fluorenyl group, and an aryl group on the bridginggroup; alternatively, a bridged hafnium based metallocene compound witha fluorenyl group, and an aryl group on the bridging group; oralternatively, a bridged zirconium or hafnium based metallocene compoundwith a cyclopentadienyl group and fluorenyl group, and an aryl group onthe bridging group. In these and other aspects, the aryl group on thebridging group can be a phenyl group. Optionally, these bridgedmetallocenes can contain an alkenyl substituent (e.g., a terminalalkenyl group) on the bridging group and/or on a cyclopentadienyl-typegroup.

In some aspects, the metallocene compound can comprise a bridgedzirconium or hafnium based metallocene compound with two indenyl groups(e.g., a bis-indenyl metallocene compound). Hence, the metallocenecompound can comprise a bridged zirconium based metallocene compoundwith two indenyl groups, or alternatively, a bridged hafnium basedmetallocene compound with two indenyl groups. In some aspects, an arylgroup can be present on the bridging group, while in other aspects,there are no aryl groups present on the bridging group. Optionally,these bridged indenyl metallocenes can contain an alkenyl substituent(e.g., a terminal alkenyl) on the bridging group and/or on the indenylgroup (one or both indenyl groups). The bridging atom of the bridginggroup can be, for instance, a single carbon atom or a single siliconatom; alternatively, the bridge can contain a chain of two carbon atoms,a chain of two silicon atoms, and so forth.

Illustrative and non-limiting examples of bridged metallocene compounds(e.g., with zirconium or hafnium) that can be employed in catalystsystems consistent with aspects of the present invention are describedin U.S. Pat. Nos. 7,026,494, 7,041,617, 7,226,886, 7,312,283, 7,517,939,and 7,619,047.

In some aspects of this invention, the metallocene compound can comprisean unbridged metallocene; alternatively, an unbridged zirconium orhafnium based metallocene compound and/or an unbridged zirconium and/orhafnium based dinuclear metallocene compound; alternatively, anunbridged zirconium or hafnium based metallocene compound containing twocyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl andan indenyl group; alternatively, an unbridged zirconium basedmetallocene compound containing two cyclopentadienyl groups, two indenylgroups, or a cyclopentadienyl and an indenyl group. Illustrative andnon-limiting examples of unbridged metallocene compounds (e.g., withzirconium or hafnium) that can be employed in catalyst systemsconsistent with aspects of the present invention are described in U.S.Pat. Nos. 7,199,073, 7,226,886, 7,312,283, and 7,619,047.

Moreover, the metallocene compound can comprise an unbridged dinuclearmetallocene such as those described in U.S. Pat. Nos. 7,919,639 and8,080,681. The metallocene compound can comprise an unbridged zirconiumand/or hafnium based dinuclear metallocene compound. For example, themetallocene compound can comprise an unbridged zirconium basedhomodinuclear metallocene compound, or an unbridged hafnium basedhomodinuclear metallocene compound, or an unbridged zirconium and/orhafnium based heterodinuclear metallocene compound (i.e., a dinuclearcompound with two hafniums, or two zirconiums, or one zirconium and onehafnium).

Aspects of this invention also are directed to catalyst compositions andmethods of preparing catalyst compositions in which two or moremetallocene compounds are employed, e.g., a dual metallocene catalystcomposition. Independently, each respective metallocene compound can beany bridged metallocene compound disclosed herein or any unbridgedmetallocene compound disclosed herein. If two metallocene compounds arepresent in the catalyst composition, the weight ratio of the firstcompound to the second compound (first:second) typical can range from50:1 to 1:50, from 10:1 to 1:10, from 5:1 to about 1:5, from 2:1 to 1:2,from 1.5:1 to 1:1.5, or from 1.2:1 to 1:1.2.

Activator-Supports

The present invention encompasses various catalyst compositions that cancontain an activator-support. In one aspect, the activator-support cancomprise a solid oxide treated with an electron-withdrawing anion.Alternatively, in another aspect, the activator-support can comprise asolid oxide treated with an electron-withdrawing anion, the solid oxidecontaining a Lewis-acidic metal ion. Non-limiting examples of suitableactivator-supports are disclosed in, for instance, U.S. Pat. Nos.7,294,599, 7,601,665, 7,884,163, 8,309,485, 8,623,973, and 8,703,886.

The solid oxide can encompass oxide materials such as alumina, “mixedoxides” thereof such as silica-alumina, coatings of one oxide onanother, and combinations and mixtures thereof. The mixed oxides such assilica-alumina can be single or multiple chemical phases with more thanone metal combined with oxygen to form the solid oxide. Examples ofmixed oxides that can be used to form an activator-support, eithersingly or in combination, can include, but are not limited to,silica-alumina, silica-titania, silica-zirconia, alumina-titania,alumina-zirconia, zinc-aluminate, alumina-boria, silica-boria,aluminophosphate-silica, titania-zirconia, and the like. The solid oxideused herein also can encompass oxide materials such as silica-coatedalumina, as described in U.S. Pat. No. 7,884,163.

Accordingly, in one aspect, the solid oxide can comprise silica,alumina, silica-alumina, silica-coated alumina, aluminum phosphate,aluminophosphate, heteropolytungstate, titania, silica-titania,zirconia, silica-zirconia, magnesia, boria, zinc oxide, any mixed oxidethereof, or any combination thereof. In another aspect, the solid oxidecan comprise alumina, silica-alumina, silica-coated alumina, aluminumphosphate, aluminophosphate, heteropolytungstate, titania,silica-titania, zirconia, silica-zirconia, magnesia, boria, or zincoxide, as well as any mixed oxide thereof, or any mixture thereof. Inanother aspect, the solid oxide can comprise silica, alumina, titania,zirconia, magnesia, boria, zinc oxide, any mixed oxide thereof, or anycombination thereof. In yet another aspect, the solid oxide can comprisesilica-alumina, silica-coated alumina, silica-titania, silica-zirconia,alumina-boria, or any combination thereof. In still another aspect, thesolid oxide can comprise alumina, silica-alumina, silica-coated alumina,or any mixture thereof; alternatively, alumina; alternatively,silica-alumina; or alternatively, silica-coated alumina.

The silica-alumina or silica-coated alumina solid oxide materials whichcan be used can have an silica content from 5% by weight to 95% byweight. In one aspect, the silica content of these solid oxides can befrom 10% by weight to 80% silica by weight, or from 20% by weight to 70%silica by weight. In another aspect, such materials can have silicacontents ranging from 15% to 60% silica by weight, or from 25% to 50%silica by weight. The solid oxides contemplated herein can have anysuitable surface area, pore volume, and particle size, as would berecognized by those of skill in the art.

The electron-withdrawing component used to treat the solid oxide can beany component that increases the Lewis or Brønsted acidity of the solidoxide upon treatment (as compared to the solid oxide that is not treatedwith at least one electron-withdrawing anion). According to one aspect,the electron-withdrawing component can be an electron-withdrawing anionderived from a salt, an acid, or other compound, such as a volatileorganic compound, that serves as a source or precursor for that anion.Examples of electron-withdrawing anions can include, but are not limitedto, sulfate, bisulfate, fluoride, chloride, bromide, iodide,fluorosulfate, fluoroborate, phosphate, fluorophosphate,trifluoroacetate, triflate, fluorozirconate, fluorotitanate,phospho-tungstate, tungstate, molybdate, and the like, includingmixtures and combinations thereof. In addition, other ionic or non-ioniccompounds that serve as sources for these electron-withdrawing anionsalso can be employed. It is contemplated that the electron-withdrawinganion can be, or can comprise, fluoride, chloride, bromide, phosphate,triflate, bisulfate, or sulfate, and the like, or any combinationthereof, in some aspects provided herein. In other aspects, theelectron-withdrawing anion can comprise sulfate, bisulfate, fluoride,chloride, bromide, iodide, fluorosulfate, fluoroborate, phosphate,fluorophosphate, trifluoroacetate, triflate, fluorozirconate,fluorotitanate, and the like, or combinations thereof. Yet, in otheraspects, the electron-withdrawing anion can comprise fluoride and/orsulfate.

The activator-support generally can contain from 1 wt. % to 30 wt. % ofthe electron-withdrawing anion, based on the weight of theactivator-support. In particular aspects provided herein, theactivator-support can contain from 2 to 20 wt. %, from 2 to 15 wt. %,from 2 to 10 wt. %, from 3 to 18 wt. %, from 3 to 15 wt. %, or from 3 to10 wt. %, of the electron-withdrawing anion, based on the total weightof the activator-support.

In an aspect, the activator-support can comprise fluorided alumina,chlorided alumina, bromided alumina, sulfated alumina, phosphatedalumina, fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, phosphated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, and the like, as well as any mixture or combination thereof. Inanother aspect, the activator-support employed in the catalyst systemsdescribed herein can be, or can comprise, a fluorided solid oxide, asulfated solid oxide, a phosphated solid oxide, or a combinationthereof. In yet another aspect, the activator-support can comprisefluorided silica-alumina, fluorided silica-coated alumina, sulfatedalumina, or any combination thereof. In still another aspect, theactivator-support can comprise fluorided alumina; alternatively,chlorided alumina; alternatively, sulfated alumina; alternatively,fluorided silica-alumina; alternatively, sulfated silica-alumina;alternatively, fluorided silica-zirconia; alternatively, chloridedsilica-zirconia; alternatively, sulfated silica-coated alumina;alternatively, fluorided-chlorided silica-coated alumina; oralternatively, fluorided silica-coated alumina. In some aspects, theactivator-support can comprise a fluorided solid oxide, while in otheraspects, the activator-support can comprise a sulfated solid oxide.

Various processes can be used to form activator-supports useful in thepresent invention. Methods of contacting the solid oxide with theelectron-withdrawing component, suitable electron withdrawing componentsand addition amounts, impregnation with metals or metal ions (e.g.,zinc, nickel, vanadium, titanium, silver, copper, gallium, tin,tungsten, molybdenum, zirconium, and the like, or combinations thereof),and various calcining procedures and conditions are disclosed in, forexample, U.S. Pat. Nos. 6,107,230, 6,165,929, 6,294,494, 6,300,271,6,316,553, 6,355,594, 6,376,415, 6,388,017, 6,391,816, 6,395,666,6,524,987, 6,548,441, 6,548,442, 6,576,583, 6,613,712, 6,632,894,6,667,274, 6,750,302, 7,294,599, 7,601,665, 7,884,163, and 8,309,485.Other suitable processes and procedures for preparing activator-supports(e.g., fluorided solid oxides and sulfated solid oxides) are well knownto those of skill in the art.

Organoaluminum Compounds

The present invention encompasses various catalyst compositionscontaining an organoaluminum compound, and various methods of preparingcatalyst compositions using an organoaluminum compound. As disclosedherein, more than one organoaluminum compound can be used in theprocesses and catalyst systems disclosed herein.

In some aspects, any first organoaluminum compound and secondorganoaluminum compound, independently, can have the formula,(R^(Z))₃Al, wherein each R^(Z) independently can be an aliphatic grouphaving from 1 to 10 carbon atoms. For example, each R^(Z) independentlycan be methyl, ethyl, propyl, butyl, hexyl, or isobutyl. In otheraspects, suitable first organoaluminum compounds and secondorganoaluminum compounds, independently, can have the formula,Al(X⁷)_(m)(X⁸)_(3-m), wherein each X⁷ independently can be ahydrocarbyl; each X¹ independently can be an alkoxide or an aryloxide, ahalide, or a hydride; and m can be from 1 to 3, inclusive. Hydrocarbylis used herein to specify a hydrocarbon radical group and includes, forinstance, aryl, alkyl, cycloalkyl, alkenyl, cycloalkenyl,cycloalkadienyl, alkynyl, aralkyl, aralkenyl, and aralkynyl groups. Inone aspect, each X⁷ independently can be any hydrocarbyl having from 1to about 18 carbon atoms, or from 1 to about 8 carbon atoms, or an alkylhaving from 1 to 10 carbon atoms. For example, each X⁷ independently canbe methyl, ethyl, propyl, n-butyl, sec-butyl, isobutyl, or hexyl, andthe like, in certain aspect of the present invention. According toanother aspect of the present invention, each X⁸ independently can be analkoxide or an aryloxide, any one of which has from 1 to 18 carbonatoms, a halide, or a hydride. In yet another aspect of the presentinvention, each X⁸ can be selected independently from fluorine andchlorine. In the formula, Al(X⁷)_(m)(X⁸)_(3-m), m can be a number from 1to 3 (inclusive) and typically, m can be 3. The value of m is notrestricted to be an integer; therefore, this formula can includesesquihalide compounds or other organoaluminum cluster compounds.

Examples of first organoaluminum compounds and second organoaluminumcompounds suitable for use in accordance with the present invention caninclude, but are not limited to, trialkylaluminum compounds,dialkylaluminum halide compounds, dialkylaluminum alkoxide compounds,dialkylaluminum hydride compounds, and combinations thereof. Specificnon-limiting examples can include trimethylaluminum (TMA),triethylaluminum (TEA), tri-n-propylaluminum (TNPA), tri-n-butylaluminum(TNBA), triisobutylaluminum (TIBA), tri-n-hexylaluminum,tri-n-octylaluminum, diisobutylaluminum hydride, diethylaluminumethoxide, diethylaluminum chloride, and the like, or combinationsthereof. Herein, the first organoaluminum compound and the secondorganoaluminum compound can be the same in one aspect, and the firstorganoaluminum compound and the second organoaluminum compound can bedifferent in another aspect.

For instance, the first organoaluminum compound and the secondorganoaluminum compound can be the same or different and independentlycan comprise (or consist essentially of, or consist of)triisobutylaluminum, tri-n-octylaluminum, or a mixture oftriisobutylaluminum and tri-n-octylaluminum at any suitable relativeamount of the different organoaluminum compounds.

Hydrocarbon Solvents

Various hydrocarbon solvents can be utilized in step (a) to form themetallocene solution. For example, the hydrocarbon solvent can comprisea linear alkane compound, a branched alkane compound, a cyclic alkanecompound, or a combination thereof. Additionally or alternatively, thehydrocarbon solvent can comprise an aromatic compound, such as benzene,toluene, xylene, and the like, as well as substituted versions thereof,and including combinations thereof. Additionally or alternatively, thehydrocarbon solvent can comprise a linear olefin compound (e.g., anα-olefin), a branched olefin compound, a cyclic olefin compound, or acombination thereof.

Any suitable carbon number hydrocarbon can be used, and therefore, thehydrocarbon solvent can comprise any suitable carbon number alkanecompound, for instance, a C₁ to C₃₆ alkane compound; alternatively, a C₁to C₁₈ alkane compound; alternatively, a C₁ to C₁₂ alkane compound; oralternatively, a C₁ to C₈ alkane compound. The hydrocarbon solvent cancomprise a mixture of two or more hydrocarbons, such as two or morealkane compounds in any relative proportions. Similarly, the hydrocarbonsolvent can comprise any suitable carbon number olefin compound, forinstance, a C₂ to C₆ olefin compound; alternatively, a C₂ to C₁₈ olefincompound; alternatively, a C₂ to C₁₂ olefin compound; or alternatively,a C₂ to C₈ olefin compound. The hydrocarbon solvent can comprise amixture of two or more hydrocarbons, such as two or more olefincompounds in any relative proportions. Likewise, the hydrocarbon solventcan comprise any suitable carbon number aromatic compound, for instance,a C₆ to C₆ aromatic compound; alternatively, a C₆ to C₁₈ aromaticcompound; alternatively, a C₆ to C₁₂ aromatic compound; oralternatively, a C₆ to C₈ aromatic compound. The hydrocarbon solvent cancomprise a mixture of two or more hydrocarbon solvents, such as two ormore aromatic compounds in any relative proportions.

Illustrative examples of alkane, olefin, and aromatic hydrocarbonsolvents can include pentane (e.g., n-pentane, neopentane, cyclopentane,or isopentane), hexane (e.g., hexane or cyclohexane), heptane (e.g.,n-heptane or cycloheptane), octane (e.g., n-octane or iso-octane),nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane,hexadecane, heptadecane, octadecane, methylcyclohexane,methylcycloheptane, 1-butene, 1-pentene, 2-pentene, 1-hexene, 1-heptene,1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene, cyclopentene, cyclohexene, benzene, toluene, ethylbenzene,xylene, and the like, as well as combinations thereof.

In an aspect, the hydrocarbon (alkane) solvent can comprise n-pentane,neopentane, cyclopentane, isopentane, hexane, cyclohexane, n-heptane,cycloheptane, n-octane, iso-octane, and the like, or any combinationthereof, while in another aspect, the hydrocarbon (alkane) solvent cancomprise heptane, such as n-heptane and/or cycloheptane. In yet anotheraspect, the hydrocarbon (olefin) solvent can comprise 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, and the like, or anycombination thereof; alternatively, 1-butene; alternatively, 1-hexene;or alternatively, 1-octene. In still another aspect, the hydrocarbon(aromatic) solvent can comprise benzene, toluene, ethylbenzene, xylene,or any combination thereof; alternatively, ethylbenzene and/or benzene;alternatively, toluene; or alternatively, xylene.

Polymerization Processes

In one aspect, a first polymerization process consistent with thisinvention can comprise contacting a catalyst composition (any catalystcomposition disclosed herein, or a catalyst composition produced by anyprocess disclosed herein) with ethylene and an optional olefin comonomerin a polymerization reactor system under polymerization conditions toproduce an ethylene polymer.

Unexpectedly, this first polymerization process can produce ethylenepolymers with a large amount of LCBs. For instance, a LCB content of theethylene polymer produced by the first polymerization process can begreater (e.g., by at least 10%, by at least 25%, by at least 50%, by atleast 75%, or by at least 100%, and often up to 600%, up to 500%, up to300%, or up to 200%) than a LCB content of an ethylene polymer producedunder the same polymerization conditions using a catalyst systemobtained without the first organoaluminum compound (or obtained bycombining the activator-support, the metallocene compound, thehydrocarbon solvent, and the second organoaluminum compound). Thus, moreLCB content results from the use of the first organoaluminum compound inpreparing the metallocene solution. The same polymerization conditionsrefer to slurry polymerization conditions, using isobutane as a diluent,and with a polymerization temperature of 90° C. and a reactor pressureof 390 or 420 psig. Moreover, all components used to prepare thecatalyst systems are held constant (e.g., same amount/type ofmetallocene compound, same amount/type of second organoaluminum, sameamount/type of activator-support, same amount/type of hydrocarbonsolvent, and all polymerization conditions are held constant (e.g., samepolymerization temperature and same polymerization pressure). Hence, theonly difference is the method used to produce the catalyst system, i.e.,the use of the first organoaluminum compound to prepare the metallocenesolution.

In another aspect, a second polymerization process consistent with thisinvention (also can be referred to as a method of controlling LCBcontent) can comprise (A) contacting a metallocene compound, ahydrocarbon solvent, and a first organoaluminum compound for a firstperiod of time to form a metallocene solution, and contacting themetallocene solution with an activator-support and a secondorganoaluminum compound for a second period of time to form a high LCBcatalyst composition, (B) contacting the metallocene compound, thehydrocarbon solvent, the activator-support, and the secondorganoaluminum compound to form a low LCB catalyst composition, (C)contacting the high LCB catalyst composition and/or the low LCB catalystcomposition with ethylene and an optional olefin comonomer in apolymerization reactor system under polymerization conditions to producean ethylene polymer having a long chain branch (LCB) content, and (D)controlling a relative amount of the high LCB catalyst composition andthe low LCB catalyst composition in step (C) to adjust the LCB contentof the ethylene polymer. Thus, the LCB content of the ethylene polymercan be controlled or varied by controlling the relative amount of thehigh LCB catalyst composition and the low LCB catalyst composition usedin the ethylene-based polymerization process.

Notably, step (A) of this second polymerization process can be performedas described herein for step (a) and step (b) of the processes forproducing a catalyst composition disclosed herein—in this case, thecatalyst composition that produces ethylene polymers with higher amountsof LCBs. Step (B) is a conventional catalyst preparation process, inwhich the metallocene compound, the hydrocarbon solvent, the secondorganoaluminum compound, and the activator-support are contacted to forma low LCB catalyst composition—which produces ethylene polymers withlower amounts of LCBs.

In an aspect, the high LCB catalyst composition and the low LCB catalystcomposition can be fed separately (e.g., in separate feed streams) to areactor in the polymerization reactor system. In another aspect, thehigh LCB catalyst composition and the low LCB catalyst composition canmixed (e.g., in a suitable vessel) and the resulting mixture can be fedto a reactor in the polymerization reactor system.

In yet another aspect encompassed herein, the metallocene solutioncontaining the metallocene compound, the hydrocarbon solvent, and thefirst organoaluminum compound can be fed to a catalyst preparationvessel than contains the activator-support and the second organoaluminumcompound to form the high LCB catalyst composition, and a mixture of themetallocene compound and the hydrocarbon solvent also can be fed to thecatalyst preparation vessel that contains the activator-support and thesecond organoaluminum compound to form the low LCB catalyst composition.In this aspect, the high LCB catalyst composition and the low LCBcatalyst composition are effectively formed simultaneously in thecatalyst preparation vessel, prior to being fed to a reactor in thepolymerization reactor system. Thus, the relative amount of themetallocene solution versus the mixture (metallocene compound andhydrocarbon solvent, with no first organoaluminum compound) that is fedto the catalyst preparation vessel can be used to control the relativeamount of the high LCB catalyst composition versus the low LCB catalystcomposition.

Any suitable weight ratio of the high LCB catalyst composition to thelow LCB catalyst composition can be used in the second polymerizationprocess to produce the desired amount of LCB content. Typical weightratios of the high LCB catalyst composition to the low LCB catalystcomposition can include from 100:1 to 1:100, from 10:1 to 1:10, from 5:1to 1:5, or from 2:1 to 1:2, and the like.

Optionally, the second polymerization process can further comprise thesteps of determining (or measuring) the LCB content of the ethylenepolymer, and adjusting the relative amount of the high LCB catalystcomposition and the low LCB catalyst composition in step (C) based onthe difference between the measured LCB content and a target LCBcontent. Thus, for example, if the LCB content of the ethylene polymeris lower than the desired target LCB content, the ratio of the amount ofthe high LCB catalyst composition to the low LCB catalyst compositioncan be increased, thereby increasing the LCB content of the ethylenepolymer.

In both the first polymerization process and the second polymerizationprocess, the LCB content of the ethylene polymer is not particularlylimited, and often is targeted based on fabrication process and endproduct performance considerations in the end-use application of theethylene polymer. Nonetheless, the ethylene polymer generally cancontain from 1 to 150 LCBs per million total carbon atoms, such as from1 to 10 LCBs, from 10 to 150 LCBs, or from 15 to 100 LCBs, per milliontotal carbon atoms.

Referring to both the first and second polymerization processes, a“polymerization reactor” includes any polymerization reactor capable ofpolymerizing olefin monomers and comonomers (one or more than onecomonomer) to produce homopolymers, copolymers, terpolymers, and thelike. The various types of polymerization reactors include those thatcan be referred to as a batch reactor, slurry reactor, gas-phasereactor, solution reactor, high pressure reactor, tubular reactor,autoclave reactor, and the like, or combinations thereof; oralternatively, the polymerization reactor system can comprise a slurryreactor, a gas-phase reactor, a solution reactor, or a combinationthereof. The polymerization conditions for the various reactor types arewell known to those of skill in the art. Gas phase reactors can comprisefluidized bed reactors or staged horizontal reactors. Slurry reactorscan comprise vertical or horizontal loops. High pressure reactors cancomprise autoclave or tubular reactors. Reactor types can include batchor continuous processes. Continuous processes can use intermittent orcontinuous product discharge. Polymerization reactor systems andprocesses also can include partial or full direct recycle of unreactedmonomer, unreacted comonomer, and/or diluent.

A polymerization reactor system can comprise a single reactor ormultiple reactors (2 reactors, more than 2 reactors, etc.) of the sameor different type. For instance, the polymerization reactor system cancomprise a slurry reactor, a gas-phase reactor, a solution reactor, or acombination of two or more of these reactors. Production of polymers inmultiple reactors can include several stages in at least two separatepolymerization reactors interconnected by a transfer device making itpossible to transfer the polymers resulting from the firstpolymerization reactor into the second reactor. The desiredpolymerization conditions in one of the reactors can be different fromthe operating conditions of the other reactor(s). Alternatively,polymerization in multiple reactors can include the manual transfer ofpolymer from one reactor to subsequent reactors for continuedpolymerization. Multiple reactor systems can include any combinationincluding, but not limited to, multiple loop reactors, multiple gasphase reactors, a combination of loop and gas phase reactors, multiplehigh pressure reactors, or a combination of high pressure with loopand/or gas phase reactors. The multiple reactors can be operated inseries, in parallel, or both. Accordingly, the present inventionencompasses polymerization reactor systems comprising a single reactor,comprising two reactors, and comprising more than two reactors. Thepolymerization reactor system can comprise a slurry reactor, a gas-phasereactor, a solution reactor, in certain aspects of this invention, aswell as multi-reactor combinations thereof.

According to one aspect, the polymerization reactor system can compriseat least one loop slurry reactor comprising vertical or horizontalloops. Monomer, diluent, catalyst, and comonomer can be continuously fedto a loop reactor where polymerization occurs. Generally, continuousprocesses can comprise the continuous introduction of monomer/comonomer,a catalyst, and a diluent into a polymerization reactor and thecontinuous removal from this reactor of a suspension comprising polymerparticles and the diluent. Reactor effluent can be flashed to remove thesolid polymer from the liquids that comprise the diluent, monomer and/orcomonomer. Various technologies can be used for this separation stepincluding, but not limited to, flashing that can include any combinationof heat addition and pressure reduction, separation by cyclonic actionin either a cyclone or hydrocyclone, or separation by centrifugation.

A typical slurry polymerization process (also known as the particle formprocess) is disclosed, for example, in U.S. Pat. Nos. 3,248,179,4,501,885, 5,565,175, 5,575,979, 6,239,235, 6,262,191, 6,833,415, and8,822,608.

Suitable diluents used in slurry polymerization include, but are notlimited to, the monomer being polymerized and hydrocarbons that areliquids under reaction conditions. Examples of suitable diluentsinclude, but are not limited to, hydrocarbons such as propane,cyclohexane, isobutane, n-butane, n-pentane, isopentane, neopentane, andn-hexane. Some loop polymerization reactions can occur under bulkconditions where no diluent is used.

According to yet another aspect, the polymerization reactor system cancomprise at least one gas phase reactor (e.g., a fluidized bed reactor).Such reactor systems can employ a continuous recycle stream containingone or more monomers continuously cycled through a fluidized bed in thepresence of the catalyst under polymerization conditions. A recyclestream can be withdrawn from the fluidized bed and recycled back intothe reactor. Simultaneously, polymer product can be withdrawn from thereactor and new or fresh monomer can be added to replace the polymerizedmonomer. Such gas phase reactors can comprise a process for multi-stepgas-phase polymerization of olefins, in which olefins are polymerized inthe gaseous phase in at least two independent gas-phase polymerizationzones while feeding a catalyst-containing polymer formed in a firstpolymerization zone to a second polymerization zone. Representative gasphase reactors are disclosed in U.S. Pat. Nos. 5,352,749, 4,588,790,5,436,304, 7,531,606, and 7,598,327.

According to still another aspect, the polymerization reactor system cancomprise a high pressure polymerization reactor, e.g., can comprise atubular reactor or an autoclave reactor. Tubular reactors can haveseveral zones where fresh monomer, initiators, or catalysts are added.Monomer can be entrained in an inert gaseous stream and introduced atone zone of the reactor. Initiators, catalysts, and/or catalystcomponents can be entrained in a gaseous stream and introduced atanother zone of the reactor. The gas streams can be intermixed forpolymerization. Heat and pressure can be employed appropriately toobtain optimal polymerization reaction conditions.

According to yet another aspect, the polymerization reactor system cancomprise a solution polymerization reactor wherein the monomer/comonomerare contacted with the catalyst composition by suitable stirring orother means. A carrier comprising an inert organic diluent or excessmonomer can be employed. If desired, the monomer/comonomer can bebrought in the vapor phase into contact with the catalytic reactionproduct, in the presence or absence of liquid material. Thepolymerization zone can be maintained at temperatures and pressures thatwill result in the formation of a solution of the polymer in a reactionmedium. Agitation can be employed to obtain better temperature controland to maintain uniform polymerization mixtures throughout thepolymerization zone. Adequate means are utilized for dissipating theexothermic heat of polymerization.

The polymerization reactor system can further comprise any combinationof at least one raw material feed system, at least one feed system forcatalyst or catalyst components, and/or at least one polymer recoverysystem. Suitable reactor systems can further comprise systems forfeedstock purification, catalyst storage and preparation, extrusion,reactor cooling, polymer recovery, fractionation, recycle, storage,loadout, laboratory analysis, and process control. Depending upon thedesired properties of the olefin polymer, hydrogen can be added to thepolymerization reactor as needed (e.g., continuously, pulsed, etc.).

Polymerization conditions that can be controlled for efficiency and toprovide desired polymer properties can include temperature, pressure,and the concentrations of various reactants. Polymerization temperaturecan affect catalyst productivity, polymer molecular weight, andmolecular weight distribution. Various polymerization conditions can beheld substantially constant, for example, for the production of aparticular grade of the olefin polymer (or ethylene polymer). A suitablepolymerization temperature can be any temperature below thede-polymerization temperature according to the Gibbs Free energyequation. Typically, this includes from 60° C. to 280° C., for example,or from 60° C. to 120° C., depending upon the type of polymerizationreactor(s). In some reactor systems, the polymerization temperaturegenerally can be within a range from 70° C. to 100° C., or from 75° C.to 95° C.

Suitable pressures will also vary according to the reactor andpolymerization type. The pressure for liquid phase polymerizations in aloop reactor is typically less than 1000 psig (6.9 MPa). Pressure forgas phase polymerization is usually from 200 to 500 psig (1.4 MPa to 3.4MPa). High pressure polymerization in tubular or autoclave reactors isgenerally run at 20,000 to 75,000 psig (138 to 517 MPa). Polymerizationreactors can also be operated in a supercritical region occurring atgenerally higher temperatures and pressures. Operation above thecritical point of a pressure/temperature diagram (supercritical phase)can offer advantages to the polymerization reaction process.

The concentration of the reactants entering the polymerization reactorcan be controlled to produce resins with certain physical and mechanicalproperties. The proposed end-use product that will be formed by thepolymer resin and the method of forming that product ultimately candetermine the desired polymer properties and attributes. Mechanicalproperties include tensile, flexural, impact, creep, stress relaxation,and hardness tests. Physical properties include density, molecularweight, molecular weight distribution, melting temperature, glasstransition temperature, temperature melt of crystallization,stereoregularity, crack growth, long chain branching, and rheologicalmeasurements.

Consistent with aspects of this invention, the olefin monomer used inthe polymerization process is ethylene, and if used, the comonomer cancomprise a C₃-C₂₀ alpha-olefin; alternatively, a C₃-C₁₀ alpha-olefin;alternatively, the comonomer can comprise 1-butene, 1-pentene, 1-hexene,1-octene, 1-decene, styrene, or any combination thereof; alternatively,the comonomer can comprise 1-butene, 1-hexene, 1-octene, or anycombination thereof; alternatively, the comonomer can comprise 1-butene;alternatively, the comonomer can comprise 1-hexene; or alternatively,the comonomer can comprise 1-octene. Thus, in an aspect, the catalystcomposition (or the high LCB catalyst composition and/or the low LCBcatalyst composition) can contacted with ethylene and an olefincomonomer comprising a C₃-C₁₀ alpha-olefin to produce the ethylenepolymer, while in another aspect, the catalyst composition (or the highLCB catalyst composition and/or the low LCB catalyst composition) can becontacted with ethylene and an olefin comonomer comprising 1-butene,1-hexene, 1-octene, or a mixture thereof, to produce the ethylenepolymer.

In one aspect, the ethylene polymer of this invention can comprise anethylene/α-olefin copolymer, while in another aspect, the ethylenepolymer can comprise an ethylene homopolymer, and in yet another aspect,the ethylene polymer of this invention can comprise an ethylene/α-olefincopolymer and an ethylene homopolymer. For example, the ethylene polymercan comprise an ethylene/1-butene copolymer, an ethylene/1-hexenecopolymer, an ethylene/1-octene copolymer, an ethylene homopolymer, orany combination thereof; alternatively, an ethylene/1-butene copolymer,an ethylene/1-hexene copolymer, an ethylene/1-octene copolymer, or anycombination thereof; or alternatively, an ethylene/1-hexene copolymer.

Aspects contemplated herein also are directed to, and encompass, theethylene polymers produced by any of the polymerization processesdisclosed herein. Articles of manufacture can be formed from, and/or cancomprise, the polymers produced in accordance with the polymerizationprocesses described herein.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, modifications, and equivalentsthereof which, after reading the description herein, can suggestthemselves to one of ordinary skill in the art without departing fromthe spirit of the present invention or the scope of the appended claims.

Sulfated alumina (SA) activator-supports were prepared as follows. Analumina having a surface area of 300 m²/g, a pore volume of 1.3 mL/g,and an average particle size of 100 microns, was calcined in air at 600°C. for 15 min and then allowed to cool. Next, 100 g of the alumina wereimpregnated with 300 mL of water into which 15 g of concentratedsulfuric acid had been dissolved. The resulting damp powder was thendried overnight under vacuum at 100° C. Calcining was performed at 600°C. by fluidizing the sulfated alumina (14.7 wt. % sulfate) in drynitrogen for 3 hr, followed by cooling to room temperature while stillbeing fluidized under nitrogen.

Fluorided silica-coated alumina (FSCA) activator-supports were preparedas follows. A slurry was made by mixing 400 mL of water and 100 g ofsilica-coated alumina (40 wt. % alumina, a surface area of 450 m²/g, apore volume of 1.3 mL/g, and an average particle size of 35 microns). Asolution of concentrated hydrofluoric acid (5 g HF) was mixed into theslurry, and the resulting slurry was then spray dried to a dry flowablepowder. Calcining was performed at 600° C. by fluidizing the fluoridedsilica-coated alumina (4.75 wt. % fluoride) in dry nitrogen for 3 hr,followed by cooling to room temperature while still being fluidizedunder nitrogen.

The metallocene compounds used in the examples are abbreviated asfollows: MET-A is rac-ethylene-bis(indenyl) zirconium dichloride; MET-Bis bis-indenyl zirconium dichloride; MET-C ismethyl(buten-3-yl)methylidene(η5-cyclopentadienyl)(η5-2,7-di-tert-butylfluoren-9-ylidene)zirconium dichloride; and MET-D is bis(n-butyl cyclopentadienyl)zirconium dichloride. The organoaluminum compounds used in the examplesare abbreviated as follows: TIBA is triisobutylaluminum, TEA istriethylaluminum, TOA is trioctylaluminum, and TMA is trimethylaluminum.

Molecular weights and molecular weight distributions were obtained usinga PL-GPC 220 (Polymer Labs, an Agilent Company) system equipped with aIR4 detector (Polymer Char, Spain) and three (3) Styragel HMW-6E GPCcolumns (Waters, MA) running at 145° C. The flow rate of the mobilephase 1,2,4-trichlorobenzene (TCB) containing 0.5 g/L2,6-di-t-butyl-4-methylphenol (BHT) was set at 1 mL/min, and polymersolution concentrations were approximately 1 mg/mL, depending on themolecular weight. Sample preparation was conducted at 150° C. fornominally 4 hr with occasional and gentle agitation, before thesolutions were transferred to sample vials for injection. An injectionvolume of about 400 μL was used. The integral calibration method wasused to deduce molecular weights and molecular weight distributionsusing a broad Chevron Phillips Chemical Company's HDPE polyethyleneresin, MARLEX BHB5003, as the standard. The integral table of thestandard was pre-determined in a separate experiment with SEC-MALS. Mnis the number-average molecular weight, Mw is the weight-averagemolecular weight, Mz is the z-average molecular weight, and Mp is thepeak molecular weight (location, in molecular weight, of the highestpoint of the molecular weight distribution curve).

Melt rheological characterizations were performed as follows.Small-strain (10%) oscillatory shear measurements were performed on anAnton Paar MCR 501 rheometer using parallel-plate geometry. Allrheological tests were performed at 190° C. The complex viscosity |η*|versus frequency (ω) data were then curve fitted using the modifiedthree parameter Carreau-Yasuda (CY) empirical model to obtain the zeroshear viscosity—η₀, characteristic viscous relaxation time—τ_(η), andthe breadth parameter—a (CY-a parameter). The simplified Carreau-Yasuda(CY) empirical model is as follows.

${{❘{\eta*(\omega)}❘} = \frac{\eta^{0}}{\left\lbrack {1 + \left( {\tau_{\eta}\omega} \right)^{a}} \right\rbrack^{{({1 - n})}/a}}},$wherein: |η*(ω)|=magnitude of complex shear viscosity;

-   -   η₀=zero shear viscosity;    -   τ_(η)=viscous relaxation time (Tau(η) in sec);    -   a=“breadth” parameter (CY-a parameter);    -   n=fixes the final power law slope, fixed at 2/11; and    -   ω=angular frequency of oscillatory shearing deformation.

Details of the significance and interpretation of the CY model andderived parameters can be found in: C. A. Hieber and H. H. Chiang,Rheol. Acta, 28, 321 (1989); C. A. Hieber and H. H. Chiang, Polym. Eng.Sci., 32, 931 (1992); and R. B. Bird, R. C. Armstrong and O. Hasseger,Dynamics of Polymeric Liquids. Volume 1, Fluid Mechanics, 2nd Edition,John Wiley & Sons (1987).

The long chain branches (LCBs) per 1,000,000 total carbon atoms of theoverall polymer were calculated using the method of Janzen and Colby (J.Mol. Struct., 485/486, 569-584 (1999), from values of zero shearviscosity (η₀) determined from the Carreau-Yasuda model describedhereinabove, and values of Mw obtained using the GPC procedure describedhereinabove.

Examples 1-26

For Examples 1-26, Table I summarizes the metallocene solutions, TableII summarizes the catalyst compositions, and Table III summarizes thepolymerization experiments and polymer properties (Mw, η₀, and LCBs permillion total carbon atoms). The metallocene solutions were prepared atroom temperature and atmospheric pressure by first dissolving orslurrying the metallocene compound in the hydrocarbon solvent, and ifused, then adding the first organoaluminum compound (a solution inhexanes or heptanes). The metallocene solutions in Table I were preparedfor 5 minutes to 12 hours prior to the addition of the activator-support(dry solids), and then followed by adding the second organoaluminumcompound (a solution in hexanes or heptanes) to form the catalystcompositions shown in Table II. The exception was Example 24, in whichthe metallocene solution was prepared by mixing 1 mL of a stock solution(10 mg MET-C+10 mL toluene) with 0.3 mL of 1M TIBA solution for 15 min.These catalyst composition of Examples 1-26 were prepared for 5-15minutes prior to being used in ethylene polymerization experiments.

The polymerization experiments of Examples 1-26 are summarized in TableIII and were conducted for 15-54 min in a one-gallon stainless-steelautoclave reactor containing isobutane as diluent. The reactorcontaining the catalyst composition and isobutane was heated to thedesired run temperature of 90° C., and ethylene was then introduced intothe reactor (1-hexene and hydrogen were not used). Ethylene was fed ondemand to maintain the target pressure of 390-420 psig. The reactor wasmaintained at the desired temperature throughout the experiment by anautomated heating-cooling system. After venting of the reactor, purging,and cooling, the resulting polymer product was dried at 50° C. underreduced pressure. Note that Examples 19-20 were duplicates, and Examples21-22 were duplicates.

Referring to the LCB data in Table III, it is apparent that differentmetallocene compounds and different activator-supports produce ethylenepolymers with different amounts of LCBs, however it was unexpectedlyfound that the method used to prepare the catalystcomposition—regardless of the metallocene compound and theactivator-support used—also significantly affected the LCB content ofthe ethylene polymer.

In most cases, the use of the first organoaluminum compound in thepreparation of the metallocene solution resulted in an unexpectedincrease in the LCB content of the ethylene polymer (as compared toexamples in which no first organoaluminum compound was used). Thisgeneral trend also was observed regardless of the solvent used in thepreparation of the metallocene solution. Increases in LCB content of upto 100% were common, however, there were also very surprising increasesin LCB content of 100% to over 500% in certain examples (see Examples3-4, 12, 16, and 24).

Also unexpectedly, (i) the type of solvent—aromatic, alkane, orolefin—used in the preparation of the metallocene solution (along withthe metallocene compound and the first organoaluminum compound) and (ii)the species of the first organoaluminum compound both impacted the LCBcontent of the ethylene polymer.

Catalyst compositions containing MET-A that were particularly noteworthyin terms of producing ethylene polymers having relatively high LCBcontents used (a) 1-hexene or heptane as the hydrocarbon solvent andTIBA as the first organoaluminum compound, or (b) toluene or heptane asthe hydrocarbon solvent and TOA as the first organoaluminum compound.

Catalyst compositions containing MET-C (and regardless of theactivator-support used) that were particularly noteworthy in terms ofproducing ethylene polymers having relatively high LCB contents usedtoluene as the hydrocarbon solvent and TIBA as the first organoaluminumcompound.

TABLE I Metallocene Solutions - Examples 1-26. Metallocene SolutionPreparation Example Metallocene Solvent First Organoaluminum 1 MET-A (10mg) toluene (10 mL) — 2 MET-A (10 mg) toluene (9 mL) TIBA (1 mL, 1M) 3MET-A (10 mg) 1-hexene (9 mL) TIBA (1 mL, 1M) 4 MET-A (10 mg) heptane (9mL) TIBA (1 mL, 1M) 5 MET-A (10 mg) toluene (10 mL) — 6 MET-A (10 mg)toluene (9 mL) TEA (1 mL, 1M) 7 MET-A (10 mg) 1-hexene (9 mL) TEA (1 mL,1M) 8 MET-A (10 mg) heptane (9 mL) TEA (1 mL, 1M) 9 MET-A (10 mg)toluene (10 mL) — 10 MET-A (10 mg) toluene (8 mL) TOA (2 mL, 0.48M) 11MET-A (10 mg) 1-hexene (8 mL) TOA (2 mL, 0.48M) 12 MET-A (10 mg) heptane(8 mL) TOA (2 mL, 0.48M) 13 MET-A (10 mg) toluene (10 mL) — 14 MET-A (10mg) toluene (9.5 mL) TMA (0.5 mL, 2M) 15 MET-B (10 mg) toluene (10 mL) —16 MET-B (10 mg) toluene (9 mL) TIBA (1 mL, 1M) 17 MET-B (10 mg)1-hexene (9 mL) TIBA (1 mL, 1M) 18 MET-C (50 mg) toluene (25 mL) — 19MET-C (20 mg) toluene (9 mL) TIBA (1 mL, 1M) 20 MET-C (20 mg) toluene (9mL) TIBA (1 mL, 1M) 21 MET-C (20 mg) 1-hexene (9 mL) TIBA (1 mL, 1M) 22MET-C (20 mg) 1-hexene (9 mL) TIBA (1 mL, 1M) 23 MET-C (10 mg) toluene(10 mL) — 24 MET-C (1 mg)  toluene (1 mL) TIBA (0.3 mL, 1M) 25 MET-D (10mg) toluene (10 mL) — 26 MET-D (10 mg) toluene (9 mL) TIBA (1 mL, 1M)

TABLE II Catalyst Compositions - Examples 1-26. Metallocene MetalloceneSecond Total Organoaluminum Activator-Support Example solution (mL) (mg)Organoaluminum First (mmol) Second (mmol) (100 mg) 1 1 1.0 TIBA 0 0.4FSCA 2 1 1.0 TIBA 0.1 0.3 FSCA 3 1 1.0 TIBA 0.1 0.3 FSCA 4 1 1.0 TIBA0.1 0.3 FSCA 5 1 1.0 TEA 0 0.4 FSCA 6 1 1.0 TEA 0.1 0.4 FSCA 7 1 1.0 TEA0.1 0.4 FSCA 8 1 1.0 TEA 0.1 0.3 FSCA 9 1 1.0 TOA 0 0.4 FSCA 10 1 1.0TOA 0.1 0..3 FSCA 11 1 1.0 TOA 0.1 0..3 FSCA 12 1 1.0 TOA 0.1 0..3 FSCA13 1 1.0 TMA 0 0.4 FSCA 14 1 1.0 TMA 0.1 0.3 FSCA 15 1 1.0 TIBA 0 0.4FSCA 16 1 1.0 TIBA 0.1 0.3 FSCA 17 1 1.0 TIBA 0.1 0.3 FSCA 18 1 2.0 TIBA0 0.6 SA 19 1 2.0 TIBA 0.1 0.5 SA 20 1 2.0 TIBA 0.1 0.5 SA 21 1 2.0 TIBA0.1 0.5 SA 22 1 2.0 TIBA 0.1 0.5 SA 23 0.5 0.5 TIBA 0 0.4 FSCA 24 1.31.0 TIBA 0.3 0 FSCA 25 1 1.0 TIBA 0 0.4 FSCA 26 1 1.0 TIBA 0.1 0.3 FSCA

TABLE III Polymerization Experiments - Examples 1-26. Time Temp PressurePolymer LCBs Mw η₀ Example (min) (° C.) (psig) (g) (per million)(kg/mol) (Pa-sec) 1 30 90 390 179 11.6 139 1.08E+05 2 54 90 390 170 14.8145 2.74E+05 3 22 90 390 183 65.8 156 8.80E+07 4 37 90 390 174 30.9 1381.73E+06 5 30 90 390 156 11.8 112 2.66E+04 6 40 90 390 157 15.0 1196.09E+04 7 30 90 390 152 16.7 120 8.45E+04 8 39 90 390 152 12.2 1245.29E+04 9 19 90 390 162 16.6 138 2.08E+05 10 23 90 390 158 27.9 1564.17E+06 11 16 90 390 175 12 126 5.87E+04 12 42 90 390 155 ~100 1701.68E+09 13 30 90 390 40 17.4 112 5.78E+04 14 38 90 390 45 19.2 1033.74E+04 15 30 90 390 219 0.31 214 3.50E+04 16 50 90 390 215 0.77 1983.32E+04 17 35 90 390 227 0.27 209 3.18E+04 18 30 90 420 256 0.88 3172.47E+05 19 30 90 420 278 1.59 292 2.91E+05 20 30 90 420 257 1.67 3053.89E+05 21 30 90 420 205 0.97 353 4.33E+05 22 30 90 420 255 0.79 3202.37E+05 23 30 90 390 216 1.9 312 5.36E+05 24 15 90 390 315 4.3 2425.04E+05 25 42 90 390 206 0.27 182 1.94E+04 26 47 90 390 198 0.48 1741.78E+04

The invention is described above with reference to numerous aspects andspecific examples. Many variations will suggest themselves to thoseskilled in the art in light of the above detailed description. All suchobvious variations are within the full intended scope of the appendedclaims. Other aspects of the invention can include, but are not limitedto, the following (aspects are described as “comprising” but,alternatively, can “consist essentially of” or “consist of” unlessspecifically stated otherwise):

Aspect 1. A process to produce a catalyst composition, the processcomprising:

-   -   (a) contacting a metallocene compound, a hydrocarbon solvent,        and a first organoaluminum compound for a first period of time        to form a metallocene solution; and    -   (b) contacting the metallocene solution with an        activator-support and a second organoaluminum compound for a        second period of time to form the catalyst composition.

Aspect 2. A polymerization process (a method of controlling LCB content)comprising:

-   -   (A) contacting a metallocene compound, a hydrocarbon solvent,        and a first organoaluminum compound for a first period of time        to form a metallocene solution, and contacting the metallocene        solution with an activator-support and a second organoaluminum        compound for a second period of time to form a high LCB catalyst        composition;    -   (B) contacting the metallocene compound, the hydrocarbon        solvent, the activator-support, and the second organoaluminum        compound to form a low LCB catalyst composition;    -   (C) contacting the high LCB catalyst composition and/or the low        LCB catalyst composition with ethylene and an optional olefin        comonomer in a polymerization reactor system under        polymerization conditions to produce an ethylene polymer having        a long chain branch (LCB) content; and    -   (D) controlling a relative amount of the high LCB catalyst        composition and the low LCB catalyst composition in step (C) to        adjust (control, vary) the LCB content of the ethylene polymer.

Aspect 3. The process defined in aspect 1 or 2, wherein the first periodof time is in any suitable range of first time periods, e.g., from 5 secto 48 hr, from 30 sec to 6 hr, from 5 min to 1 hr, at least 5 sec, or atleast 5 min.

Aspect 4. The process defined in any one of aspects 1-3, wherein thesecond period of time is in any suitable range of second time periods,e.g., from 1 sec to 48 hr, from 1 min to 6 hr, from 5 min to 1 hr, atleast 1 min, or at least 5 min.

Aspect 5. The process defined in any one of aspects 1-4, wherein step(a) (or step (A)) comprises contacting a solution of the metallocenecompound in the hydrocarbon solvent with the first organoaluminumcompound.

Aspect 6. A catalyst composition produced by the process defined in anyone of aspects 1 or 3-5.

Aspect 7. A catalyst composition comprising:

-   -   (i) a metallocene solution comprising a metallocene compound, a        hydrocarbon solvent, and a first organoaluminum compound;    -   (ii) an activator-support; and    -   (iii) a second organoaluminum compound.

Aspect 8. A catalyst composition comprising:

-   -   (i) a metallocene solution comprising rac-ethylene-bis(indenyl)        zirconium dichloride, a hydrocarbon solvent, and a first        organoaluminum compound;    -   (ii) an activator-support; and    -   (iii) a second organoaluminum compound.

Aspect 9. A catalyst composition comprising:

-   -   (i) a metallocene solution comprising        methyl(buten-3-yl)methylidene(η5-cyclopentadienyl)(η5-2,7-di-tert-butylfluoren-9-ylidene)        zirconium dichloride, a hydrocarbon solvent, and a first        organoaluminum compound;    -   (ii) an activator-support; and    -   (iii) a second organoaluminum compound.

Aspect 10. The process or composition defined in any one of aspects 1-9,wherein the activator-support comprises a solid oxide treated with anelectron-withdrawing anion, for example, comprising any suitable solidoxide treated with any suitable electron-withdrawing anion.

Aspect 11. The process or composition defined in aspect 10, wherein thesolid oxide comprises silica, alumina, silica-alumina, silica-coatedalumina, aluminum phosphate, aluminophosphate, heteropolytungstate,titania, zirconia, magnesia, boria, zinc oxide, a mixed oxide thereof,or any mixture thereof; and the electron-withdrawing anion comprisessulfate, bisulfate, fluoride, chloride, bromide, iodide, fluorosulfate,fluoroborate, phosphate, fluorophosphate, trifluoroacetate, triflate,fluorozirconate, fluorotitanate, phospho-tungstate, tungstate,molybdate, or any combination thereof.

Aspect 12. The process or composition defined in any one of aspects 1-9,wherein the activator-support comprises a fluorided solid oxide, asulfated solid oxide, a phosphated solid oxide, or a combinationthereof.

Aspect 13. The process or composition defined in any one of aspects 1-9,wherein the activator-support comprises fluorided alumina, chloridedalumina, bromided alumina, sulfated alumina, phosphated alumina,fluorided silica-alumina, chlorided silica-alumina, bromidedsilica-alumina, sulfated silica-alumina, phosphated silica-alumina,fluorided silica-zirconia, chlorided silica-zirconia, bromidedsilica-zirconia, sulfated silica-zirconia, fluorided silica-titania,fluorided silica-coated alumina, fluorided-chlorided silica-coatedalumina, sulfated silica-coated alumina, phosphated silica-coatedalumina, or any combination thereof.

Aspect 14. The process or composition defined in any one of aspects 1-9,wherein the activator-support comprises fluorided silica-alumina,fluorided silica-coated alumina, sulfated alumina, or any combinationthereof.

Aspect 15. The process or composition defined in any one of aspects1-14, wherein the activator-support contains from 1 to 30 wt. %, from 2to 20 wt. %, from 2 to 15 wt. %, from 2 to 10 wt. %, or from 3 to 10 wt.%, of the electron-withdrawing anion, based on the total weight of theactivator-support.

Aspect 16. The process or composition defined in any one of aspects1-15, wherein the hydrocarbon solvent comprises any suitable alkane,e.g., pentane (e.g., n-pentane, neopentane, cyclopentane, orisopentane), hexane (e.g., hexane or cyclohexane), heptane (e.g.,n-heptane or cycloheptane), octane (e.g., n-octane or iso-octane), orany combination thereof; or alternatively, heptane.

Aspect 17. The process or composition defined in any one of aspects1-15, wherein the solvent comprises any suitable olefin, e.g., 1-butene,1-hexene, 1-octene, or any combination thereof; or alternatively,1-hexene.

Aspect 18. The process or composition defined in any one of aspects1-15, wherein the solvent comprise any suitable aromatic, e.g.,ethylbenzene, benzene, toluene, xylene, or any combination thereof; oralternatively, toluene.

Aspect 19. The process or composition defined in any one of aspects1-18, wherein the first organoaluminum compound and the secondorganoaluminum compound are the same or different and independentlycomprise any suitable organoaluminum compound, e.g., trimethylaluminum,triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, or any combination thereof.

Aspect 20. The process or composition defined in any one of aspects1-18, wherein the first organoaluminum compound and the secondorganoaluminum compound are the same or different and independentlycomprise triisobutylaluminum and/or tri-n-octylaluminum.

Aspect 21. The process or composition defined in any one of aspects1-20, wherein the metallocene compound comprises any suitable bridgedmetallocene compound or any bridged metallocene compound disclosedherein.

Aspect 22. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconiumbased metallocene compound with a fluorenyl group.

Aspect 23. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a cyclopentadienyl group and afluorenyl group.

Aspect 24. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a fluorenyl group, and an arylgroup and/or an alkenyl group on the bridging group.

Aspect 25. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with a cyclopentadienyl group andfluorenyl group, and an aryl group and/or an alkenyl group on thebridging group.

Aspect 26. The process or composition defined in aspect 24 or 25,wherein the aryl group is a phenyl group and the alkenyl group is aterminal alkenyl group.

Aspect 27. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconium orhafnium based metallocene compound with two indenyl groups.

Aspect 28. The process or composition defined in any one of aspects1-21, wherein the metallocene compound comprises a bridged zirconiumbased metallocene compound with two indenyl groups.

Aspect 29. The process or composition defined in one of aspects 21-28,wherein the bridging group contains a single carbon bridging atom or atwo carbon atom chain.

Aspect 30. The process or composition defined in any one of aspects1-20, wherein the metallocene compound comprises any suitable unbridgedmetallocene compound or any unbridged metallocene compound disclosedherein.

Aspect 31. The process or composition defined in any one of aspects1-20, wherein the metallocene compound comprises an unbridged zirconiumor hafnium based metallocene compound containing two cyclopentadienylgroups, two indenyl groups, or a cyclopentadienyl and an indenyl group.

Aspect 32. The process or composition defined in any one of aspects1-20, wherein the metallocene compound comprises an unbridged zirconiumbased metallocene compound containing two cyclopentadienyl groups, twoindenyl groups, or a cyclopentadienyl and an indenyl group.

Aspect 33. The process or composition defined in any one of aspects1-32, wherein a weight ratio of the metallocene compound to theactivator-support is in any suitable range of weight ratios, e.g., from1:1 to 1:100,000, from 1:10 to 1:10,000, from 1:20 to 1:1000, or from1:50 to 1:500.

Aspect 34. The process or composition defined in any one of aspects1-33, wherein a molar ratio of the first organoaluminum compound to thesecond organoaluminum compound is in any suitable range of molar ratios,e.g., from 1000:1 to 1:1000, from 100:1 to 1:100, from 10:1 to 1:10,from 1:1 to 1:10, or from 1:2 to 1:10.

Aspect 35. The process or composition defined in any one of aspects1-34, wherein a molar ratio of the first organoaluminum compound to themetallocene compound is in any suitable range of molar ratios, e.g.,from 1:1 to 1000:1, from 1:1 to 100:1, from 2:1 to 200:1, or from 5:1 to100:1.

Aspect 36. The process or composition defined in any one of aspects1-35, wherein the weight ratio of the activator-support to the secondorganoaluminum compound is in any suitable range of weight ratios, e.g.,from 100:1 to 1:100, from 10:1 to 1:10, from 5:1 to 1:5, or from 2:1 to1:2.

Aspect 37. The process or composition defined in any one of aspects1-36, wherein the catalyst composition is substantially free ofaluminoxane compounds, organoboron or organoborate compounds, ionizingionic compounds, or combinations thereof.

Aspect 38. A polymerization process comprising contacting the catalystcomposition defined in any one of aspects 1 or 3-37 with ethylene and anoptional olefin comonomer in a polymerization reactor system underpolymerization conditions to produce an ethylene polymer.

Aspect 39. The polymerization process defined in aspect 38, wherein aLCB content of the ethylene polymer produced by the process is greater(by any amount disclosed herein, e.g., at least 10%, at least 25%, atleast 50%, at least 75%, or at least 100%) than a LCB content of anethylene polymer produced under the same polymerization conditions usinga catalyst system obtained without the first organoaluminum compound (orobtained by combining the activator-support, the metallocene compound,the hydrocarbon solvent, and the second organoaluminum compound).

Aspect 40. The polymerization process defined in any one of aspects2-39, wherein the optional olefin comonomer comprise a C₃-C₂₀alpha-olefin.

Aspect 41. The polymerization process defined in any one of aspects2-40, wherein the catalyst composition (or the high LCB catalystcomposition and/or the low LCB catalyst composition) is contacted withethylene and an olefin comonomer comprising a C₃-C₁₀ alpha-olefin.

Aspect 42. The polymerization process defined in any one of aspects2-41, wherein the catalyst composition (or the high LCB catalystcomposition and/or the low LCB catalyst composition) is contacted withethylene and an olefin comonomer comprising 1-butene, 1-hexene,1-octene, or a mixture thereof.

Aspect 43. The polymerization process defined in any one of aspects2-42, wherein the polymerization reactor system comprises a batchreactor, a slurry reactor, a gas-phase reactor, a solution reactor, ahigh pressure reactor, a tubular reactor, an autoclave reactor, or acombination thereof.

Aspect 44. The polymerization process defined in any one of aspects2-43, wherein the polymerization reactor system comprises a slurryreactor, a gas-phase reactor, a solution reactor, or a combinationthereof.

Aspect 45. The polymerization process defined in any one of aspects2-44, wherein the polymerization reactor system comprises a loop slurryreactor.

Aspect 46. The polymerization process defined in any one of aspects2-45, wherein the polymerization reactor system comprises a singlereactor.

Aspect 47. The polymerization process defined in any one of aspects2-45, wherein the polymerization reactor system comprises 2 reactors.

Aspect 48. The polymerization process defined in any one of aspects2-45, wherein the polymerization reactor system comprises more than 2reactors.

Aspect 49. The polymerization process defined in any one of aspects2-48, wherein the ethylene polymer comprises an ethylene homopolymer, anethylene/1-butene copolymer, an ethylene/1-hexene copolymer, anethylene/1-octene copolymer, or any combination thereof.

Aspect 50. The polymerization process defined in any one of aspects2-48, wherein the ethylene polymer comprises an ethylene/1-hexenecopolymer.

Aspect 51. The polymerization process defined in any one of aspects2-50, wherein a weight ratio of the high LCB catalyst composition to thelow LCB catalyst composition is in any suitable range of weight ratios,e.g., from 100:1 to 1:100, from 10:1 to 1:10, from 5:1 to 1:5, or from2:1 to 1:2.

Aspect 52. The polymerization process defined in any one of aspects2-51, wherein the ethylene polymer has any suitable LCB content, e.g.,from 1 to 150 LCBs, from 1 to 10 LCBs, from 10 to 150 LCBs, or from 15to 100 LCBs, per million total carbon atoms.

Aspect 53. The polymerization process defined in any one of aspects2-52, further comprising the steps of determining (or measuring) the LCBcontent of the ethylene polymer, and adjusting the relative amount ofthe high LCB catalyst composition and the low LCB catalyst compositionin step (C) based on the difference between the measured LCB content anda target LCB content.

Aspect 54. The ethylene polymer produced by the polymerization processdefined in any one of aspects 2-53.

Aspect 55. An article comprising the ethylene polymer defined in aspect54.

We claim:
 1. A catalyst composition comprising: (i) a metallocenesolution comprising: a metallocene compound comprisingrac-ethylene-bis(indenyl) zirconium dichloride, a hydrocarbon solventcomprising an olefin solvent and/or an alkane solvent, and a firstorganoaluminum compound comprising triisobutylaluminum; (ii) anactivator-support; and (iii) a second organoaluminum compound.
 2. Thecatalyst composition of claim 1, wherein the second organoaluminumcompound comprises triisobutylaluminum and/or tri-n-octylaluminum. 3.The catalyst composition of claim 1, wherein: the second organoaluminumcompound comprises trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, or any combinationthereof.
 4. The catalyst composition of claim 1, wherein theactivator-support comprises a fluorided solid oxide, a sulfated solidoxide, a phosphated solid oxide, or a combination thereof.
 5. Thecatalyst composition of claim 1, wherein the catalyst composition issubstantially free of aluminoxane compounds, organoboron or organoboratecompounds, ionizing ionic compounds, or combinations thereof.
 6. Thecatalyst composition of claim 1, wherein: a weight ratio of themetallocene compound to the activator-support is from 1:1 to 1:100,000;and a molar ratio of the first organoaluminum compound to the secondorganoaluminum compound is from 1000:1 to 1:1000.
 7. The catalystcomposition of claim 6, wherein: the activator-support comprisesfluorided silica-alumina, fluorided silica-coated alumina, sulfatedalumina, or any combination thereof; and the hydrocarbon solventcomprises 1-hexene and/or heptane.
 8. A catalyst composition comprising:(i) a metallocene solution comprising: a metallocene compound comprisingrac-ethylene-bis(indenyl) zirconium dichloride, a hydrocarbon solventcomprising an aromatic solvent and/or an alkane solvent, and a firstorganoaluminum compound comprising trioctylaluminum; (ii) anactivator-support; and (iii) a second organoaluminum compound.
 9. Thecatalyst composition of claim 8, wherein the second organoaluminumcompound comprises triisobutylaluminum and/or tri-n-octylaluminum. 10.The catalyst composition of claim 8, wherein the second organoaluminumcompound comprises trimethylaluminum, triethylaluminum,tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, diisobutylaluminum hydride,diethylaluminum ethoxide, diethylaluminum chloride, or any combinationthereof.
 11. The catalyst composition of claim 8, wherein: theactivator-support comprises a fluorided solid oxide, a sulfated solidoxide, a phosphated solid oxide, or a combination thereof; and thecatalyst composition is substantially free of aluminoxane compounds,organoboron or organoborate compounds, ionizing ionic compounds, orcombinations thereof.
 12. The catalyst composition of claim 8, wherein:a weight ratio of the metallocene compound to the activator-support isfrom 1:1 to 1:100,000; and a molar ratio of the first organoaluminumcompound to the second organoaluminum compound is from 1000:1 to 1:1000.13. The catalyst composition of claim 6, wherein: the activator-supportcomprises fluorided silica-alumina, fluorided silica-coated alumina,sulfated alumina, or any combination thereof; and the hydrocarbonsolvent comprises toluene and/or heptane.
 14. A catalyst compositioncomprising: (i) a metallocene solution comprising: a metallocenecompound comprisingmethyl(buten-3-yl)methylidene(η5-cyclopentadienyl(η5-2,7-di-tert-butylfluoren-9-ylidene)zirconium dichloride, a hydrocarbon solvent comprising an aromaticsolvent, and a first organoaluminum compound comprisingtriisobutylaluminum; (ii) an activator-support; and (iii) a secondorganoaluminum compound.
 15. The catalyst composition of claim 14,wherein the second organoaluminum compound comprises triisobutylaluminumand/or tri-n-octylaluminum.
 16. The catalyst composition of claim 14,wherein the second organoaluminum compound comprises trimethylaluminum,triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum,triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum,diisobutylaluminum hydride, diethylaluminum ethoxide, diethylaluminumchloride, or any combination thereof.
 17. The catalyst composition ofclaim 14, wherein the activator-support comprises a fluorided solidoxide, a sulfated solid oxide, a phosphated solid oxide, or acombination thereof.
 18. The catalyst composition of claim 14, whereinthe catalyst composition is substantially free of aluminoxane compounds,organoboron or organoborate compounds, ionizing ionic compounds, orcombinations thereof.
 19. The catalyst composition of claim 14, wherein:a weight ratio of the metallocene compound to the activator-support isfrom 1:1 to 1:100,000; and a molar ratio of the first organoaluminumcompound to the second organoaluminum compound is from 1000:1 to 1:1000.20. The catalyst composition of claim 19, wherein: the activator-supportcomprises fluorided silica-alumina, fluorided silica-coated alumina,sulfated alumina, or any combination thereof; and the hydrocarbonsolvent comprises toluene.